The invention is a high line speed S-Z stranding device for S-Z stranding one or more coated optical fibers and/or buffer tubes, in which optical fibers are disposed. Devices for S-Z stranding buffer tubes are well known and are exemplified by U.S. Pat. Nos. 4,429,521, which teaches a horizontal S-Z stranding device and 4,458,476, which discloses a vertical S-Z stranding device. The disclosures of both of the aforementioned patents are incorporated herein by reference.
Some S-Z stranding prior art disclosures use the term "tube store". A tube store is an elongated member about which coated optical fibers and/or buffer tubes containing optical fibers are S-Z stranded. Throughout this disclosure, such an elongated member is referred to as an "elongated accumulator". In most prior art S-Z stranding disclosures, there is taught methods and apparatus of disposing along the longitudinal axis of an elongated accumulator a plurality of tubes in which optical fibers are disposed and rotating the elongated accumulator in first one direction and then in another direction (a reversing manner), creating what is known in the art as an S-Z strand. The present invention carries out the same steps, but with an improvement that increases line speed.
Line speed is the length of time it takes an elongated buffer tube, as it is being S-Z stranded, to longitudinally travel from one end of an elongated accumulator to the other. The faster the line speed the higher the production and of course the faster the line speed, the faster the elongated accumulator must be rotated (in a reversing manner) in order to accommodate the increased line speed. It has been found that if no less than 124 pounds of tensile force is applied along longitudinal axis of the elongated accumulator as it is rotated, the faster it can be rotated thus achieving faster line speeds. The amplitude of vibration of the elongated accumulator, arising out of higher rotational speeds, is reduced to a tolerable level by such tensile forces.